| Instrument | Purpose | Conversion Method | Shunt/Series Resistance Formula | Resulting Scale | | :--- | :--- | :--- | :--- | :--- | | | Measures current (in A) | Connect a low resistance (shunt) in parallel with the galvanometer. | ( S = \fracI_g R_gI - I_g ) | Low resistance, high range | | Voltmeter | Measures voltage (in V) | Connect a high resistance (multiplier) in series with the galvanometer. | ( R_s = \fracVI_g - R_g ) | High resistance, low range |